Images of people arriving at refugee camps in east Africa this week have brought home the stark reality of the impact of drought in the region.

Many have walked for days or weeks to get to the camps, carrying children and a few possessions. In some cases, older people have been brought in wheelbarrows or in makeshift carts.

Those arriving at camps like Dadaab in northern Kenya, now home to nearly 400,000, are the "lucky ones", still in need of additional support and food, but finally protected and cared for by a system that is stretched, but working to avert a fully-fledged famine.

At the end of June, I travelled to one of the worst drought-affected areas in Ethiopia – the Borena region on the southern border with Kenya – and came across a number of settlements. Lying around these settlements were the carcasses of animals that had endured two of the driest years in the past 60; animals whose grazing lands have been reduced year on year due to climate change brought about by the excesses of people in developed countries. And by the inability of rich countries to respond in time.

HelpAge and other international organisations working in Ethiopia have known that the situation was becoming very serious since the end of last year. The early warning systems to prevent the horror of the 1984 famine in Ethiopia from happening again are in place and working well.

Weather predictions showed that this drought was going to be very bad and where it was going to hit. But when HelpAge, and others, tried to get money from the international community to ensure there would be sufficient food, delivered in time to prevent unnecessary suffering, there weren't enough people streaming across international borders in search of help, and there were no photos of starving babies to provoke a reaction.

Because of this we were unable to prevent the current tragedy from happening. But we could - and should - have.

The governments in east Africa need to do more – and do it better – to help prepare for these recurring crises. But the people who are suffering the most, those families who have done their best to feed their children and parents, have done little or nothing to create this crisis. It is climate change and the failure of people and governments to respond in time that have done this. It is time for this to change.

HelpAge and Cafod have been providing assistance to people in Borena for two months, working with four local organisations to provide money so that families can buy what they need and feed for the livestock that are still alive and most likely to be able to reproduce once the drought is over. Those animals too weak to survive are being killed. The meat from those animals is supposed to be distributed to older people and people with disabilities, plus women and young children who are left in the region, but often there isn't enough meat left on the animals.

Our response to the crisis started before the media and major donors took notice – we persuaded the UN to give us money, for which we are very grateful – which means we will be able to make sure that the pastoralists who are suffering most will have a livelihood to return to when this crisis is over.

But too many responses are short-term, and focus on solving the immediate need only. There is an urgent need to increase funding for those affected now, but as Baroness Amos said this week, it is also vital to ensure that future crises – and there is no doubt there will be more droughts in east Africa – are prevented at an earlier stage. We need to take notice of the early warning systems that have been put in place and act before images of starving children make the front pages again.

• Alison Rusinow is country programme director for HelpAge International in Ethiopia. HelpAge is the sister organisation to Age UK, a member of the Disasters Emergency Committee (DEC). The DEC launched its east Africa crisis appeal on Thursday.